The present invention relates to a deep boring machine having a spindle unit which is horizontally displaceable on a machine bed and is driven by a spindle drive. The spindle unit has a horizontal spindle shaft for receiving a boring tool, the head of which when beginning to bore a workpiece is guided in a jig bushing disposed in a jig bushing holder that is displaceable in the direction of the spindle shaft. Deep boring machines of this kind are known.
In these deep boring machines, the clamping table or clamping stock is located in the same plane in which the jig bushing holder is also displaceable. Accordingly, the possibilities for clamping the workpieces are necessarily considerably restricted. In particular with very small workpieces, one must approach quite close to the edge of the clamping table in order to reach the clamped workpiece with the jig bushing holder at all. In specialized machining processes, such as pull boring, a bracing counter-holder must also be used. The counter-holder must rest on the other side of the workpiece. This can usually be accomplished only with a lantern that projects out a long way.
Other disadvantages are associated with this problematic clamping of the workpiece, such as the transference of spindle drive vibrations onto the clamping table, guide carriages and counter-holder carriages and insufficient rigidity of the clamping, in the event that clamping must be effected outside the center of the clamping table.